Update documentation and code to put mixin first

docs/topics/search/indexing.rst

@@ -216,7 +216,7 @@ To do this, inherit from ``index.Indexed`` and add some ``search_fields`` to the
 
     from wagtail.wagtailsearch import index
 
-    class Book(models.Model, index.Indexed):
+    class Book(index.Indexed, models.Model):
         title = models.CharField(max_length=255)
         genre = models.CharField(max_length=255, choices=GENRE_CHOICES)
         author = models.ForeignKey(Author)

docs/topics/snippets.rst

@@ -191,7 +191,7 @@ If a snippet model inherits from ``wagtail.wagtailsearch.index.Indexed``, as des
   ...
 
   @register_snippet
-  class Advert(models.Model, index.Indexed):
+  class Advert(index.Indexed, models.Model):
       url = models.URLField(null=True, blank=True)
       text = models.CharField(max_length=255)
 

wagtail/tests/search/migrations/0001_initial.py

@@ -28,7 +28,7 @@ class Migration(migrations.Migration):
                 ('live', models.BooleanField(default=False)),
                 ('published_date', models.DateField(null=True)),
             ],
-            bases=(models.Model, wagtail.wagtailsearch.index.Indexed),
+            bases=(wagtail.wagtailsearch.index.Indexed, models.Model),
         ),
         migrations.CreateModel(
             name='SearchTestChild',

wagtail/tests/snippets/migrations/0002_searchablesnippet.py

@@ -19,6 +19,6 @@ class Migration(migrations.Migration):
                 ('id', models.AutoField(serialize=False, primary_key=True, auto_created=True, verbose_name='ID')),
                 ('text', models.CharField(max_length=255)),
             ],
-            bases=(models.Model, wagtail.wagtailsearch.index.Indexed),
+            bases=(wagtail.wagtailsearch.index.Indexed, models.Model),
         ),
     ]

wagtail/tests/snippets/models.py

@@ -47,7 +47,7 @@ class RegisterDecorator(models.Model):
 # A snippet model that inherits from index.Indexed can be searched on
 
 @register_snippet
-class SearchableSnippet(models.Model, index.Indexed):
+class SearchableSnippet(index.Indexed, models.Model):
     text = models.CharField(max_length=255)
 
     search_fields = [

wagtail/wagtailcore/migrations/0001_initial.py

@@ -96,7 +96,7 @@ class Migration(migrations.Migration):
             options={
                 'abstract': False,
             },
-            bases=(models.Model, wagtail.wagtailsearch.index.Indexed),
+            bases=(wagtail.wagtailsearch.index.Indexed, models.Model),
         ),
         migrations.RunPython(
             set_page_path_collation, migrations.RunPython.noop

wagtail/wagtailcore/migrations/0001_squashed_0016_change_page_url_path_to_text_field.py

@@ -240,7 +240,7 @@ class Migration(migrations.Migration):
             options={
                 'abstract': False,
             },
-            bases=(models.Model, wagtail.wagtailsearch.index.Indexed),
+            bases=(wagtail.wagtailsearch.index.Indexed, models.Model),
         ),
         migrations.RunPython(
             set_page_path_collation, migrations.RunPython.noop

wagtail/wagtailcore/models.py

@@ -290,7 +290,7 @@ class PageBase(models.base.ModelBase):
 
 
 @python_2_unicode_compatible
-class Page(six.with_metaclass(PageBase, MP_Node, ClusterableModel, index.Indexed)):
+class Page(six.with_metaclass(PageBase, MP_Node, index.Indexed, ClusterableModel)):
     title = models.CharField(
         verbose_name=_('title'),
         max_length=255,